SIM800L cannot connect to network

Hi all,

Since this morning I've been able to communicate from my Arduino Uno to my SIM800L EVB module.
However, the module does not seem to be able to connect to my network. I'm pretty sure the network and simcard enable 2G and GPRS,and I have also disables the PINcode on the sim.

This is what a couple of AT commands give in return. Any suggestions anyone? Where is it going wrong?

+CPIN: READY

Call Ready

SMS Ready
AT+COPS=?

+COPS: (1,"Mobistar","mobi*","20610"),(1,"PROXIMUS","PROXI","

AT+COPS?

+COPS: 0

OK

capglider:
I'm pretty sure the network and simcard enable 2G and GPRS

This is something you need to be certain about.

Nick_Pyner:
This is something you need to be certain about.

Meanwhile I picked up a new SIM from another provider. It is 2G compatible for sure.

Try checking signal strength and network connection AT commands.

capglider:
Meanwhile I picked up a new SIM from another provider. It is 2G compatible for sure.

I assume you know that because you actually asked before you bought, and I hope you also asked how long the 2G service will last. Since 3G is on its way out I imagine anybody's 2G is just a grace and favour thing.

I did check 2G compatibility with provider. This is what I get now:
FYI: My SIM is from provider "Proximus", so I would expect to get connected to that network. Signal strength already seems lot better then with the SIM I used berfore from another provider...

Initializing...
AT

OK
AT+CSQ

+CSQ: 19,0

OK
AT+CCID

ERROR
AT+CREG?

+CREG: 0,0

OK
AT+CSQ

+CSQ: 19,0

OK
AT+COPS=?

+COPS: (2,"PROXIMUS","PROXI","20601"),(1,"BASE","BASE","20620AT+COPS?

+COPS: 0

OK

Additional info:
I power the module straight from the Arduino with 5V. According to the specs this typeofmodule (SIM800L EVB) is able to handle up to 5V.
However, I notice two things:

  • the power LED is ON
  • the network LED blinks fast (= "no network" ) for about 7 to 8 times
  • then the power LED goes off, then on again and the cycle starts all over again

Could there be a power / current issue?

I would recommend using a power supply capable of >2 amps. You will know when power supply is sufficient when the Net led is flashing at the correct rate and connected to network.

Also be sure that you are in an area of good network coverage as if not it will keep flashing fast.

Put the sim in a mobile to check and also send and receive a few SMS’s to confirm all ok.

itmoto:
I would recommend using a power supply capable of >2 amps. You will know when power supply is sufficient when the Net led is flashing at the correct rate and connected to network.

Also be sure that you are in an area of good network coverage as if not it will keep flashing fast.

Put the sim in a mobile to check and also send and receive a few SMS’s to confirm all ok.

Thx fot this input. Have just tested the SIM in an old phone: coverage is OK as well as sending/receiving SMS. Will work on power supply and keep you posted.

Meanwhile I am using a Lipo battery with buck convertor to provide a steady power to the module directly (so not using Arduino power output). I can now observe the "net" LED flashing once every 3 seconds, meaning that the SIM module is connected to the network. Great, one step further as compared to last post...

Using below sample code for testing though, the serial monitor does not show anything beyond "Initializing.....". This status does nog change, even after 10 minutes or more. Obviously (I guess...) there is no response to AT commands.

For info:

  • the SIM800L EVB is connected to an Arduino Nano
  • the Nano is powered via USB from a laptop. I have tried several laptops, no difference here

What could be the issues here?

#include <SoftwareSerial.h>

//Create software serial object to communicate with SIM800L
SoftwareSerial mySerial(3,2); //SIM800L Tx & Rx is connected to Arduino #3 & #2

void setup()
{
  //Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
  Serial.begin(9600);
  
  //Begin serial communication with Arduino and SIM800L
  mySerial.begin(9600);

  Serial.println("Initializing...");
  delay(1000);

  mySerial.println("AT"); //Once the handshake test is successful, it will back to OK
  updateSerial();
  mySerial.println("AT+CSQ"); //Signal quality test, value range is 0-31 , 31 is the best
  updateSerial();
  mySerial.println("AT+CCID"); //Read SIM information to confirm whether the SIM is plugged
  updateSerial();
  mySerial.println("AT+CREG?"); //Check whether it has registered in the network
  updateSerial();
}

void loop()
{
  updateSerial();
}

void updateSerial()
{
  delay(500);
  while (Serial.available()) 
  {
    mySerial.write(Serial.read());//Forward what Serial received to Software Serial Port
  }
  while(mySerial.available()) 
  {
    Serial.write(mySerial.read());//Forward what Software Serial received to Serial Port
  }
}

If you are using a buck converter, presume the lipo is greater than 1s so voltage is 8.4v stepping down to 5V?

Have you connected all grounds (lipo - Sim800 - controller) together?

itmoto:
If you are using a buck converter, presume the lipo is greater than 1s so voltage is 8.4v stepping down to 5V?

Have you connected all grounds (lipo - Sim800 - controller) together?

Lipo is 3S, so 11.1V, stepping down to 5V indeed.
All grounds have not been connected together. Will give that a try in a minute and let you know.

Have tried to combine the grounds in different ways. Does not make any difference unfortunately.

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